Debugging why KRB5_KTNAME isn't working

[Ken Hornstein]

>I am trying to debug why having KRB5_KTNAME set in the environment of a
>process is not actually making that process use that keytab file but
>instead is using the default /etc/krb5.keytab.
>
>The process is Postfix's SMTP deamon (smtpd).
>[...]
>Any thoughts/ideas?

Is it possible Postfix is clearing out the environment at startup?  I'm
a little unclear if the "environ" file in proc shows the _current_
environment or just the environment at process start (a very brief
test suggests to me that "environ" contains the environment at process
start and modification of the current environment isn't reflected there,
so if Postfix was resetting the environment you wouldn't know it).

--Ken